Re: 186 casting double hump heads
041s ARE double-humps. Some of the casting numbers you see the most are 461 (no bolt holes), 462, 492, 186, 041, 041X, 291 (no bolt holes), 292 (over-the-counter GM race head)
Those used to be the heads we all ran, for years and years, back before CNC casting made possible the whole aftermarket head industry as we know it. Before World or Dart or AFR or Edelbrock or Trick Flow or Pro Topline. Back before there was any such thing as a "street" "aftermarket" head. Or one for any purpose but the most hard-core racing, for that matter.
As has been said, good heads, for their day; among the best. Good for low-mid 400s HP on modern pump gas, given the CR you have to run these days; which will take a typical steel car to mid 12s if the car is set up well. Among the best stock heads of all time until Vortecs. But certainly not "competitive" in a heads-up sense any longer, except for a fun cheep street machine. And they're still great for that.